Comparing 3DCRT and inversely optimized IMRT planning for head and neck cancer: Equivalence between step-and-shoot and sliding window techniques

With the Varian planning and delivery system, Step-and-shoot approximations of inversely optimised fluences in head-neck IMRT compare well with SW delivery, even with only five intensity levels. With a number of intensity level of 10 or more, no differences can be appreciated in PTV coverage/OAR sparing with respect to SW.